The invention relates to a component, in particular to a housing of a high-pressure fuel pump, in which at least one first high-pressure channel and one second high-pressure channel are present, the longitudinal axis of the first channel being at an acute or right angle to the longitudinal axis of the second channel and the second channel leading into the first channel such that an intersection is formed, wherein the first channel is formed by a central bore and at least one secondary bore that enlarges the cross-section of the central bore, wherein the longitudinal axis of the secondary bore and the longitudinal axis of the central bore extend parallel to one another.
Such a component is, for example, known as a housing of a piston pump of a fuel system. By means of said piston pump, the fuel is compressed to a very high pressure and pressed into a fuel high-pressure accumulator, in particular into a fuel collecting line (“fuel rail”) or into integrated accumulators of accumulator injectors. The fuel is stored there under very high pressure. A plurality of injection valves are connected to the fuel rail, the injection valves injecting the fuel directly into the respective combustion chambers associated with said injection valves.
In the known components of this type, the fuel is compressed in conveying chambers, which are present in the housing, by corresponding pistons. The highly compressed fuel from the individual conveying chambers arrives at a common outlet, the so-called pump collector, via flow channels, which are introduced into the housing or into housing parts of the high-pressure fuel pump in the form of bores. Out of each conveying chamber, a flow channel or, respectively, bore leads into the pump collector, wherein the flow channels are at an angle >0° with respect to the pump collector. A bore intersection is formed in each case at the interface of the flow channels with the pump collector.
Due to the pressure of up to 2,200 bar prevailing in the components of fuel injection systems subjected to high-pressure, stresses occur in the pipes and channels carrying the mediums. In the pipes, axial stresses, radial stresses and stresses in the circumferential direction occur, from which the stresses in the circumferential direction make up the largest proportion of the pipe stresses. Particularly high stresses in the form of tensile stresses in the material occur at the bore intersections, in particular in the case of acute angles, on account of the overlap of the stresses from the two or plurality of bores. The maximum stress is achieved directly at the intersection edge. These locations are particularly prone to breakage when the pressures are not constant, i.e. with a pulsating load. It is therefore primarily necessary to reduce the circumferential stresses.
In this connection, it has already been proposed to enlarge the cross-section of the first channel at least in the region where the second channel leads into the same by introducing at least one, in particular two, secondary bore(s) that enlarge(s) the cross-section of the central bore. If the longitudinal axes of the secondary bores and the central bore enclose in each case an acute angle with each other, this is referred to as a “fan intersection” or a “telescope intersection”. The longitudinal axes of the central bore and the secondary bores converge hereby in the direction towards a high pressure connection of the first channel. The disadvantage of this configuration is the fact that the central bore and the secondary bores each have to be bored from both sides of the component, which leads to a high sensitivity with respect to manufacturing tolerances and to high costs.